1. Field of the Invention
The present invention relates to a film that can be inscribed by a laser beam, which has at least one protective layer than is substantially penetrable by a laser beam, on whose underside a medium that is changeable by the laser beam is arranged, whereby the medium that is changeable by the laser beam has an opaque layer that is ablatable by the laser beam and at least one contrastive colored layer that is substantially resistant to the laser beam.
By xe2x80x9cinscribingxe2x80x9d, it is to be understood that what is meant are graphical symbols and characters of each type. The protective layer can be a plastic film, a protective lacquer layer, or the like, for example.
2. Description of Related Art
A film of this type is known from the international disclosure WO98/16397. The medium that is changeable by laser beam of the known film has a contrastive layer with coloration under a metallic layer that is ablatable by means of the laser beam, the metallic layer having a coloration or dye that is different from that of the contrastive layer. By xe2x80x9cablationxe2x80x9d, what is to be understood is, therefore, the erosion or destruction of a layer, which thereby loses its opaqueness.
If surface components in the form of letters or graphical symbols are ablated by laser action on the metallic layer, these characters are recognizable in the color or dye of the contrastive layer through the protective layer, while the non-ablated region remains visible in the dye of the metallization. The laser action takes place from the side of the protective layer through the protective film.
Of course, one remains limited with the use of the inscribable film according to the type of the film described in WO09/16397, which relates to the colored appearance, as far as one wishes to justifiably maintain the manufacturing expense: The ablated region appears through the protective layer in the color of the contrastive layer, the non-ablated region in the color of the metallization. With the commonly used metallization, generally black or silver white metallization takes place. Therefore, the possible inkings that are available are white or varicolored inscription with a black background or black or multicolored inscription with a silver white background. Indeed, other colors of metallization are contemplated in principle, however, if the colors available for supply, in particular, when one takes into consideration the price of many xe2x80x9cvaricoloredxe2x80x9d metals or their application as a thin layer, one is limited to a minimal number from which to choose. Simple color printing of the protective layer is eliminated in most, since film that can be inscribed by laser is used in a first line there, where one, on the basis of the durability against abrasion or bleaching out, must grant exception to printed films.
The invention, subsequently, is based on the problem of producing a film that can be inscribed with a laser beam, which offers a large choice of colors. To this purpose, the positive qualities of common laser-inscribable films should be retained. This means that with inscription with the laser beam, practically no health endangering and environmentally damaging emissions should be produced, and the prepared, inscribed labels, identification plates, etc., should offer large, imminent protection of the lettering relative to chemical and mechanical specifications, that is, among other considerations, a good durability against wear and bleaching out.
The problem is resolved with a film that can be inscribed by a laser beam, which has at least one protective layer that is substantially penetrable by a laser beam, on whose under side, a medium that is changeable by the leaser beam is arranged, which has an opaque layer that is ablatable by the laser beam and at least one contrastive layer that is substantially resistance against the laser beam, whereby at least one of the protective layers to be substantially penetrated by the laser beam is dyed through. Therewith, the color impression of the layer visible through the protective layer is affected by the coloring of the protective layer. For example, the non-ablated part of a silver white metallization appears gold-colored through a yellow, dyed-through protective layer.
In one advantageous further embodiment of the invention, the medium that is changeable by the laser beam has at least one further, opaque layer than is ablatable by the laser beam. In this manner, a translucent, dyed-through layer (that is, a substantially penetrable and substantially transparent layer for the laser beam) is arranged between the layers that are ablatable by the laser beam. This allows realization of also sectionally, multicolored inscribing with one and the same foil, whereby the writing color also can be varied first upon the inscribing process itself, as the case may be, if one removes none, multiple, or all superimposed, associated ablatable layers at a selected point.
It is advantageous if at least one of the opaque layers that is ablatable by the laser beam is predominantly metallic. In this manner, the metallization can be steamed on or sputtered, for example, on translucent film. Preferably, the metallic layers are aluminum layers.
In a further embodiment of the invention, at least one of the ablatable layers contains metal oxide, whereby also non-stoichiometric metal oxides and mixtures of metals and metal oxides can be contained.
In a further embodiment of the present invention, the contrastive layer includes multiple regions of differing colors or dyes.
In a particularly preferred embodiment of the present invention, the medium that is changeable by the laser beam has a self-adhesive layer on its under side, whereby the inscribed film can be mounted in a simple manner on a support surface. Preferably, the film previously is arranged on a carrier course coated with an adhesive, from which the film can be pulled before application on the support surface.
In a further advantageous embodiment, the protective layer is provided on its upper side with an adhesive layer, whereby it is suited for use as a rear glass, for example, in automobile rear windows.
Additional adaptations of the visual operation of the present invention can be achieved, in which one prints or lacquers the protective layer at least partially.
In a particularly preferred embodiment of the present invention, the film has stampings, which subdivides the film into individual surface regions, for example, individual character labels, identification plates, or placards. The surface regions, then, can be detached in an advantageous manner and, for example, mechanically mounted on objects to be designated.
In a further advantageous embodiment of the present invention, the film is mountable onto a support surface and has additional safety stampings, which makes impossible undesired removal of the film from the support without at least a partial destruction of the film.
In a further embodiment of the present invention, the film is subdivided by action of a laser beam into individual, at least partially detachable surface regions.
Next, the invention will be described in more detail with reference to the schematically represented embodiments. The illustrations should explain the layer structure of the inventive embodiments, whereby the dimensions are not reproduced according to scale.